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   1 #ifndef __M68KNOMMU_UACCESS_H
   2 #define __M68KNOMMU_UACCESS_H
   3
   4 /*
   5  * User space memory access functions
   6  */
   7 #include <linux/sched.h>
   8 #include <linux/mm.h>
   9 #include <linux/string.h>
  10
  11 #include <asm/segment.h>
  12
  13 #define VERIFY_READ     0
  14 #define VERIFY_WRITE    1
  15
  16 #define access_ok(type,addr,size)       _access_ok((unsigned long)(addr),(size))
  17
  18 /*
  19  * It is not enough to just have access_ok check for a real RAM address.
  20  * This would disallow the case of code/ro-data running XIP in flash/rom.
  21  * Ideally we would check the possible flash ranges too, but that is
  22  * currently not so easy.
  23  */
  24 static inline int _access_ok(unsigned long addr, unsigned long size)
  25 {
  26         return 1;
  27 }
  28
  29 /*
  30  * The exception table consists of pairs of addresses: the first is the
  31  * address of an instruction that is allowed to fault, and the second is
  32  * the address at which the program should continue.  No registers are
  33  * modified, so it is entirely up to the continuation code to figure out
  34  * what to do.
  35  *
  36  * All the routines below use bits of fixup code that are out of line
  37  * with the main instruction path.  This means when everything is well,
  38  * we don't even have to jump over them.  Further, they do not intrude
  39  * on our cache or tlb entries.
  40  */
  41
  42 struct exception_table_entry
  43 {
  44         unsigned long insn, fixup;
  45 };
  46
  47 /* Returns 0 if exception not found and fixup otherwise.  */
  48 extern unsigned long search_exception_table(unsigned long);
  49
  50
  51 /*
  52  * These are the main single-value transfer routines.  They automatically
  53  * use the right size if we just have the right pointer type.
  54  */
  55
  56 #define put_user(x, ptr)                                \
  57 ({                                                      \
  58     int __pu_err = 0;                                   \
  59     typeof(*(ptr)) __pu_val = (x);                      \
  60     switch (sizeof (*(ptr))) {                          \
  61     case 1:                                             \
  62         __put_user_asm(__pu_err, __pu_val, ptr, b);     \
  63         break;                                          \
  64     case 2:                                             \
  65         __put_user_asm(__pu_err, __pu_val, ptr, w);     \
  66         break;                                          \
  67     case 4:                                             \
  68         __put_user_asm(__pu_err, __pu_val, ptr, l);     \
  69         break;                                          \
  70     case 8:                                             \
  71         memcpy(ptr, &__pu_val, sizeof (*(ptr))); \
  72         break;                                          \
  73     default:                                            \
  74         __pu_err = __put_user_bad();                    \
  75         break;                                          \
  76     }                                                   \
  77     __pu_err;                                           \
  78 })
  79 #define __put_user(x, ptr) put_user(x, ptr)
  80
  81 extern int __put_user_bad(void);
  82
  83 /*
  84  * Tell gcc we read from memory instead of writing: this is because
  85  * we do not write to any memory gcc knows about, so there are no
  86  * aliasing issues.
  87  */
  88
  89 #define __ptr(x) ((unsigned long *)(x))
  90
  91 #define __put_user_asm(err,x,ptr,bwl)                           \
  92         __asm__ ("move" #bwl " %0,%1"                           \
  93                 : /* no outputs */                                              \
  94                 :"d" (x),"m" (*__ptr(ptr)) : "memory")
  95
  96 #define get_user(x, ptr)                                        \
  97 ({                                                              \
  98     int __gu_err = 0;                                           \
  99     typeof(x) __gu_val = 0;                                     \
 100     switch (sizeof(*(ptr))) {                                   \
 101     case 1:                                                     \
 102         __get_user_asm(__gu_err, __gu_val, ptr, b, "=d");       \
 103         break;                                                  \
 104     case 2:                                                     \
 105         __get_user_asm(__gu_err, __gu_val, ptr, w, "=r");       \
 106         break;                                                  \
 107     case 4:                                                     \
 108         __get_user_asm(__gu_err, __gu_val, ptr, l, "=r");       \
 109         break;                                                  \
 110     case 8:                                                     \
 111         memcpy((void *) &__gu_val, ptr, sizeof (*(ptr)));       \
 112         break;                                                  \
 113     default:                                                    \
 114         __gu_val = 0;                                           \
 115         __gu_err = __get_user_bad();                            \
 116         break;                                                  \
 117     }                                                           \
 118     (x) = (typeof(*(ptr))) __gu_val;                            \
 119     __gu_err;                                                   \
 120 })
 121 #define __get_user(x, ptr) get_user(x, ptr)
 122
 123 extern int __get_user_bad(void);
 124
 125 #define __get_user_asm(err,x,ptr,bwl,reg)                       \
 126         __asm__ ("move" #bwl " %1,%0"                           \
 127                  : "=d" (x)                                     \
 128                  : "m" (*__ptr(ptr)))
 129
 130 #define copy_from_user(to, from, n)             (memcpy(to, from, n), 0)
 131 #define copy_to_user(to, from, n)               (memcpy(to, from, n), 0)
 132
 133 #define __copy_from_user(to, from, n) copy_from_user(to, from, n)
 134 #define __copy_to_user(to, from, n) copy_to_user(to, from, n)
 135 #define __copy_to_user_inatomic __copy_to_user
 136 #define __copy_from_user_inatomic __copy_from_user
 137
 138 #define copy_to_user_ret(to,from,n,retval) ({ if (copy_to_user(to,from,n)) return retval; })
 139
 140 #define copy_from_user_ret(to,from,n,retval) ({ if (copy_from_user(to,from,n)) return retval; })
 141
 142 /*
 143  * Copy a null terminated string from userspace.
 144  */
 145
 146 static inline long
 147 strncpy_from_user(char *dst, const char *src, long count)
 148 {
 149         char *tmp;
 150         strncpy(dst, src, count);
 151         for (tmp = dst; *tmp && count > 0; tmp++, count--)
 152                 ;
 153         return(tmp - dst); /* DAVIDM should we count a NUL ?  check getname */
 154 }
 155
 156 /*
 157  * Return the size of a string (including the ending 0)
 158  *
 159  * Return 0 on exception, a value greater than N if too long
 160  */
 161 static inline long strnlen_user(const char *src, long n)
 162 {
 163         return(strlen(src) + 1); /* DAVIDM make safer */
 164 }
 165
 166 #define strlen_user(str) strnlen_user(str, 32767)
 167
 168 /*
 169  * Zero Userspace
 170  */
 171
 172 static inline unsigned long
 173 __clear_user(void *to, unsigned long n)
 174 {
 175         memset(to, 0, n);
 176         return 0;
 177 }
 178
 179 #define clear_user(to,n)        __clear_user(to,n)
 180
 181 #endif /* _M68KNOMMU_UACCESS_H */